How to manage Deno dependencies in one place

Question

In Deno it is possible to version the dependencies in the import statement, and there's no package.json like with npm.

But how to managed it's URLs and versions in a single place?

I will have multiple files and dependencies that will be declared all over my system.

For example:

dateUtils.ts

import { parseDate } from 'https://deno.land/[email protected]/datetime/mod.ts';

const DEFAULT_MASK = "dd-mm-yyyy";

export function parse(date: string): Date {
    return parseDate(date, DEFAULT_MASK);
};

service.ts

import { v4 } from "https://deno.land/std/uuid/mod.ts";

export function process(request: any) {
    const { token } = request;
    const isValid = v4.validate(token);

    console.log(`Token validity: ${isValid}`)

};

app.ts

import { parse } from "./dateUtil.ts";
import * as service from "./service.ts";

const date = parse("20-05-2020");
console.log(date);

const request = {
    token: "408d30e5-1e90-45e3-b299-6520feee6d76"
}
service.process(request)

Answer 1

To avoid typing https://deno.land/std/uuid/mod.ts everywhere you can use import maps

// import_map.json

{
   "imports": {
      "http/": "https://deno.land/std/http/"
   }
}

// server.ts
import { serve } from "http/server.ts";

const body = new TextEncoder().encode("Hello World\n");
for await (const req of serve(":8000")) {
  req.respond({ body });
}

deno run --importmap=import_map.json --allow-net server.ts

import maps are currently unstable, but you can use them behind --unstable flag.

---

Aside from that it's common to have a deps.ts file where you'll re-export all your dependencies.

// deps.ts
export * as path from "https://deno.land/[email protected]/path/mod.ts";
// other exports .. from

// some other file
import { path } from './deps.ts' // instead of "https://deno.land/[email protected]/path/mod.ts"
path.basename('/bar/test.txt');

Answer 2

In deno there is a convention for consolidating imports into deps.ts.

export { parseDate } from 'https://deno.land/[email protected]/datetime/mod.ts';
export { v4 } from "https://deno.land/std/uuid/mod.ts";

Exports can then be imported in other modules/scripts on your application:

import { v4 } from "./deps.ts";
import { parseDate } from './deps.ts';

const myUUID = v4.generate();
parseDate("20-05-2020", "dd-mm-yyyy")

When using this approach one should consider integrity checking & lock files:

// Add a new dependency to "src/deps.ts", used somewhere else.
export { xyz } from "https://unpkg.com/[email protected]/lib.ts";

# Create/update the lock file "lock.json".
deno cache --lock=lock.json --lock-write src/deps.ts

# Include it when committing to source control.
git add -u lock.json
git commit -m "feat: Add support for xyz using xyz-lib"
git push